What is clustering,open addressing chaining?

What is clustering,open addressing chaining?

Clustering is a common technique for statistical data analysis, which is used in many fields, including machine learning, data mining, pattern recognition, image analysis and bioinformatics. On the other hand, Chaining is a good way to resolve collisions, but it has additional memory cost to store the structure of linked-lists.When hash table is based on the open addressing strategy, all key-value pairs are stored in the hash table itself and there is no need for external data structure.